Hybrid-type gas gauge

Abstract

A hybrid-type gas gauge according to one aspect of the present invention may comprise: a substrate having a through-hole formed therein; a diaphragm that includes a first section and a second section and has a first opening formed therein; a heater disposed on one side of the first section; a temperature control unit for controlling the temperature of the heater; a first sensor, which is formed on the other side of the first section, for measuring the amount of conduction heat transferred from the heater via the first section by conduction; a second sensor, which is formed in the second section, for measuring the amount of convection heat transferred from the heater across the first opening via the air in the through-hole by convection; and a gas calculation unit that calculates the concentration of air in the through-hole and obtains information about the types of gases in the air.

Description

Hybrid type gas gauge

[0001] The present invention relates to a gas measuring device, and more specifically, to a hybrid type gas gauge that combines a conduction type and a convection type.

[0002] Gas gauges are used to measure gas concentration within a given space. For example, gas gauges utilizing heat transfer are used. These gauges consist of a heater and a thermal sensor, and are utilized to measure gas concentration by detecting changes in heat transfer characteristics according to gas concentration and analyzing the relationship between gas concentration and heat transfer. However, conventional gas gauges based on thermal conduction have a problem in that they cannot account for changes in thermal conduction characteristics due to variations in the type of gas and heater temperature.

[0003] <Prior Art Literature>

[0004] <Patent Literature>

[0005] 1. Patent Publication No. 10-2017-0039006 (April 10, 2017)

[0006] The present invention aims to solve the aforementioned problems by providing a gas gauge capable of identifying the type of gas by considering changes in thermal conductivity characteristics according to changes in heater temperature. However, this objective is exemplary and does not limit the scope of the present invention.

[0007] A hybrid type gas gauge according to one aspect of the present invention for solving the above technical problem comprises: a substrate having a through hole formed therein; a diaphragm formed on the substrate, comprising a first portion extending from one side of the substrate toward the through hole and a second portion extending from the other side of the substrate toward the through hole, wherein a first opening is formed between the first portion and the second portion that crosses the through hole; a heater disposed on one side of the first portion facing the first opening and capable of transferring heat to the surroundings; a temperature control unit for controlling the temperature of the heater by adjusting a heating current supplied to the heater; a first sensor formed on the other side of the first portion for measuring the amount of conductive heat transferred from the heater through the first portion by a conduction method; a second sensor formed on the second portion for measuring the amount of convective heat transferred from the heater through the first opening by a convection method through the air inside the through hole; and regarding the amount of conductive heat measured by the first sensor It may include a gas calculation unit that obtains information on the type and concentration of gas in the air within the through hole by using the first signal and the second signal for the amount of convective heat measured from the second sensor, and by using the first signal and the second signal obtained by changing the heating current supplied to the heater by the temperature control unit.

[0008] According to the above hybrid type gas gauge, the gas calculation unit can calculate the concentration of air in the through hole using the ratio of the first signal to the second signal.

[0009] According to the above hybrid type gas gauge, the gas calculation unit can obtain information about the type and concentration of the gas in the air by using the first signals and the second signals, respectively, obtained when the first heating power and the second heating power are supplied to the heater by the temperature control unit.

[0010] According to the above hybrid type gas gauge, the gas calculation unit can obtain information regarding the type and concentration of the gas in the air by using the first ratio of the first signal to the second signal obtained when the first heating power is supplied to the heater by the temperature control unit, and the second ratio of the first signal to the second signal obtained when the second heating power is supplied to the heater by the temperature control unit.

[0011] According to the above hybrid type gas gauge, the gas calculation unit can obtain information about the type of gas in the air by using the difference between the first ratio and the second ratio.

[0012] According to the above hybrid type gas gauge, the gas calculation unit can determine whether O2 gas and H2 gas are included in the air in addition to N2 gas by using the difference between the first ratio and the second ratio based on the case where the air is N2 gas.

[0013] According to the above hybrid type gas gauge, it further includes a transparent conductive oxide film formed on the first part where the heater is placed, and the gas calculation unit can further receive resistance information of the transparent conductive oxide film according to the heating current applied to the heater.

[0014] According to the above hybrid type gas gauge, the diaphragm includes second openings formed on both sides of the first sensor and third openings formed on both sides of the second sensor, wherein the second openings are formed to extend in a direction perpendicular to the first opening, and the third openings are formed to extend in a direction perpendicular to the first opening.

[0015] According to the hybrid type gas gauge of the embodiments of the present invention as described above, gas concentration can be determined over a wide range by utilizing thermal conduction characteristics due to thermal conduction and thermal convection, and furthermore, concentration information regarding the type of gas can be obtained through changes in thermal conduction characteristics in response to changes in the heater temperature, thereby increasing the reliability of concentration measurement. Of course, the scope of the present invention is not limited by these effects.

[0016] FIG. 1 is a schematic perspective view illustrating the structure of a gas gauge according to one embodiment of the present invention.

[0017] Figure 2 is a schematic cross-sectional view showing the structure cut along line II-II of the gas gauge in Figure 1.

[0018] FIG. 3 is a schematic cross-sectional view illustrating the structure of a gas gauge according to another embodiment of the present invention.

[0019] FIG. 4 is a schematic plan view illustrating the structure of a gas gauge according to another embodiment of the present invention.

[0020] FIG. 5 is a schematic circuit diagram showing an example of the configuration of a temperature control unit in gas gauges according to embodiments of the present invention.

[0021] FIG. 6 is a graph showing the relationship between the signal and the gas concentration measured in a hybrid type gas gauge according to embodiments of the present invention.

[0022] FIGS. 7 to 9 are graphs showing the relationship between the heating current supplied to the heater in a hybrid type gas gauge according to embodiments of the present invention and the type of gas in the air.

[0023] The first sensor (42) has a structure that is thermally connected to the heater (30) through the first part (22). The second sensor (44) has a structure formed on the second part (24) to enable thermal transfer primarily through convection by air within the first opening (A1). The gas gauge (100) can be called a hybrid type gas gauge in that it utilizes both the first sensor (42) for measuring heat conduction heat and the second sensor (44) for measuring heat convection heat.

[0024] In some embodiments, the gas gauge (100) may further include a housing (not shown) surrounding the aforementioned structure. The air within the housing may be in communication with the air within the through hole (12). Accordingly, the air within the through hole (120) in the gas gauge (100) is filled with air within the object to be measured by the gas gauge (100) and may optionally be sealed from the outside.

[0025] In some embodiments, the gas gauge (100) may include a gas calculation unit (60). The gas calculation unit (60) can calculate the concentration of air in the through hole (12) using a first signal for conductive heat quantity measured from the first sensor (42) and a second signal for convective heat quantity measured from the second sensor (42). For example, the gas calculation unit (60) can calculate the concentration of air in the through hole (12) using the ratio of the first signal to the second signal, such as the ratio of the first signal to the second signal or the ratio of the second signal to the first signal.

[0026] However, if the heat generated by the heater (30) is inaccurate, the results of such concentration measurements may differ. To accurately measure the heat generated by the heater (30), there is a method of measuring the current and voltage of the heater (30), but there are problems that make it difficult to accurately determine due to environmental changes such as external humidity and changes due to the aging of the thin film state of the heater (30). To solve this problem, the heat generation state of the heater (30) can be monitored using a conductivity sensor. For example, the heat generated by the heater (30) can be received by the first sensor (42) to directly monitor the heat generation state of the heater (30).

[0027] In some embodiments, the gas calculation unit (60) can obtain information about the type and concentration of gas in the air by using the first signal of the first sensor (42) and the second signal of the second sensor (42) obtained by changing the heating current supplied to the heater (30) by the temperature control unit (65).

[0028] For example, information regarding the type and concentration of gas can be obtained by using a first signal and a second signal obtained by changing the heating current supplied to the heater (30) by the temperature control unit (65). For example, information regarding the type of gas can be obtained by utilizing the fact that the trends of the first signal and the second signal change depending on the temperature of the heater (30), and furthermore, the concentration can be calculated using this gas information.

[0029] In some embodiments, the gas calculation unit (65) can determine the type and concentration of gas in the air using first signals and second signals obtained respectively when various heating powers, such as first heating power and second heating power, are supplied to the heater (30) by the temperature control unit (65).

[0030] For example, the gas calculation unit (65) can obtain information about the type and concentration of gas in the air by using the first ratio of the first signal to the second signal obtained when the first heating power is supplied to the heater (30) by the temperature control unit (65) and the second ratio of the first signal to the second signal obtained when the second heating power is supplied to the heater (30) by the temperature control unit (65).

[0031] For example, the gas calculation unit (65) can obtain information about the type of gas in the air by using the difference between the first ratio and the second ratio described above. The gas calculation unit (65) can determine whether O2 gas and H2 gas are included in the air in addition to N2 gas by using the difference between the first ratio and the second ratio, based on the case where the air is N2 gas.

[0032] FIG. 3 is a schematic cross-sectional view illustrating the structure of a gas gauge (100a) according to another embodiment of the present invention. The gas gauge (100a) is a modified version of the gas gauge (100) described above, and since the two embodiments can be referenced to each other, a redundant description is omitted.

[0033] Referring to FIG. 3, the gas gauge (100a) may further include a transparent conductive oxide (TCO) formed on a first portion where a heater (30) is placed. The gas calculation unit (65) may further receive resistance information of the transparent conductive oxide (TCO) according to the heating current supplied to the heater (30). For example, the gas calculation unit (65) may cross-check the gas concentration calculation result using this resistance information.

[0034] FIG. 4 is a schematic plan view illustrating the structure of a gas gauge (100b) according to another embodiment of the present invention. The gas gauge (100b) according to this embodiment is a modified version of some configurations of the gas gauges (100, 100a) of FIG. 1 to 4, and since the embodiments can be referenced to one another, redundant descriptions in the embodiments are omitted.

[0035] Referring to FIG. 4, in the gas gauge (100b), the heater (30) is formed in the form of a heating wire in the first part (22) of the diaphragm (20), and the first sensor (42) and the second sensor (44) may be provided as thermopile sensors having a hot contact and a cold contact. The first opening (A1) is formed to cross the through hole (12) between the heater (30) and the second sensor (44), and a pair of second openings (A2) are formed on both sides of the first sensor (42). A pair of third openings (A3) may be formed on both sides of the third sensor (44). In this embodiment, the first opening (A1), the second openings (A2), and the third openings (A3) may be formed within the diaphragm (20) at a certain distance apart from each other without being connected.

[0036] FIG. 5 is a schematic circuit diagram showing an example of the configuration of a temperature control unit (65) in gas gauges (100, 100a, 100b) according to embodiments of the present invention.

[0037] Referring to FIG. 5, the temperature control unit (65) may include a central processing unit (MCU), an integrator (INT), a comparator (CPT), a transistor (Tr), and a resistor (Rc).

[0038] In the temperature control unit (65), an integrator (INT) is connected to the output terminal of the digital-to-analog converter (DAC) of the central processing unit (MCU), the output of the integrator (INT) is input to a comparator (CPT), and the output of the comparator (CPT) is input to a transistor (Tr), thereby allowing the magnitude of the current supplied from the power supply unit (VCC) to be controlled. Accordingly, the temperature of the heater (30) can be controlled by adjusting the magnitude of the heating power, such as the heating current, supplied to the heater (30) using the temperature control unit (65).

[0039] The aforementioned temperature control unit (65) is exemplary and can be modified in various ways.

[0040] Below, the calculation of gas concentration and determination of gas type in gas gauges (100, 100a, 100b) will be explained.

[0041] Gas gauges (100, 100a, 100b) may include a gas calculation unit (60) for obtaining gas type information and calculating gas concentration. For example, gas gauges (100, 100a, 100b) can calculate the type and concentration of the gas in the air within the through hole (12) using a first signal for conductive heat quantity measured from a first sensor (42) and a second signal for convective heat quantity measured from a second sensor (44).

[0042] Below, a method for calculating gas concentration and obtaining information about the type of gas using the first sensor (42) and the second sensor (44) in the gas calculation unit (60) is explained in more detail.

[0043] Referring to FIG. 6, when the gas concentration changes, for example, when the concentration of hydrogen (H2) is 0%, 1%, 2%, 3.5% and the remainder is nitrogen (N2), it can be seen that the ratio (S1 / S2) of the first signal (S1) obtained from the first sensor (42) to the second signal (S2) obtained from the second sensor (44) changes as the hydrogen concentration changes. That is, it can be seen that the ratio (S1 / S2) of the first signal (S1) to the second signal (S2) increases as the hydrogen concentration increases. From this result, conversely, it can be understood that the ratio (S2 / S1) of the second signal (S2) to the first signal (S1) decreases as the hydrogen concentration increases.

[0044] Accordingly, the concentration of hydrogen can be calculated using parameters for the first signal (S1) and the second signal (S2), such as the ratio (S1 / S2) or the ratio (S2 / S1). For example, since the thermal conductivity of the mixed gas according to concentration can be obtained based on data regarding the thermal conductivity of N2 gas and the thermal conductivity of H2 gas, conversely, gas concentration information can be obtained from the thermal conductivity of the mixed gas.

[0045] FIGS. 7 to 9 are graphs showing the relationship between the heating current supplied to the heater in a hybrid type gas gauge according to embodiments of the present invention and the type of gas in the air. Three cases were used for the heating current applied to the heater (30): 1 mA (DAC1000), 2 mA (DAC2000), and 3 mA (DAC3000). Three cases were used for the air: 100% N2 (C0), 80% N2 / 20% O2 (C1), and 99% N2 / 1% H2 (C2).

[0046] Referring to FIG. 7, it can be seen that when the air conditions are changed and the heating power applied to the heater (30) is changed, the trend of the ratio (S1 / S2) of the first signal (S1) to the second signal (S2) changes.

[0047] More specifically, when the air consists of 100% nitrogen (N2) (C0), the ratio of the first signal (S2) to the second signal (S2) (S1 / S2) was almost identical in three different cases (C0, C1, C2) where the heating current was different. Therefore, based on the case where the air is N2 gas (100% N2), the ratio of the first signal (S1) to the second signal (S2) (S1 / S2) can have a reference value of 1 regardless of the temperature of the heater (30).

[0048] In the case where the air is 80% N2 / 20% O2 (C1), the ratio of the first signal (S1) to the second signal (S2) (S1 / S2) increased in the order of increasing heating current, i.e., case (DAC1000), case (DAC2000), and case (DAC3000). Therefore, based on the case where the air is N2 gas (N2 100%), it can be seen that when oxygen (O2) is included in the air, the ratio of the first signal (S1) to the second signal (S2) (S1 / S2) changes in the direction of increasing as the heating current increases.

[0049] In the case where the air is 99% N2 / 1% H2 (C2), the ratio of the first signal (S1) to the second signal (S2) (S1 / S2) decreased in the order of increasing heating current, i.e., case (DAC1000), case (DAC2000), and case (DAC3000). Therefore, based on the case where the air is N2 gas (100% N2), it can be seen that when hydrogen (H2) is included in the air, the ratio of the first signal (S1) to the second signal (S2) (S1 / S2) changes in a direction that decreases as the heating current increases.

[0050] Accordingly, from the above results, it can be seen that the type of gas in the air can be determined by using data on the ratio (S1 / S2) of the first signal (S1) to the second signal (S2) obtained by varying the temperature of the heater (30) by at least two intervals, and that the concentration can be calculated even in cases where two or more types of additive gases other than N2 are included in the air. In this case, since the thermal conductivity measured in the mixed gas can be calculated as the ratio of the concentration to the thermal conductivity of each gas, the concentration of at least two gases can be calculated from the thermal conductivity results measured at at least two temperatures.

[0051] As shown in FIG. 8, it can be seen that the ratio (S1 / S2) of the first signal (S1) to the second signal (S2) for each type of gas varies according to the temperature of the heater (30). In particular, in the case of H2 and He gases, unlike other gases, it can be seen that the ratio (S1 / S2) decreases as the temperature increases.

[0052] As illustrated in FIG. 9, the heating current applied to the heater (30) is described as an example for two different cases (DAC1000, DAC3000). The case where the difference (R2-R1) obtained by subtracting the ratio of the first signal (S1) to the second signal (S2) of case (DAC3000) (S1 / S2), i.e., R1 from R2 is 1 is the standard, in which case N2 in the air is 100%. It can be seen that if the difference (R2-R1) is greater than 1, the oxygen (O2) gas increases, and if it is less than 1, the hydrogen (H2) gas increases.

[0053] Accordingly, the gas calculation unit (60) can determine whether O2 gas and H2 gas are included in the air in addition to N2 gas by using the difference in the ratio (S1 / S2) of the first signal (S1) to the second signal (S2), based on the case where the air is N2 gas.

[0054] Accordingly, according to the gas gauges (100, 100a, 100b), the gas calculation unit (60) uses a variable that combines the first signal (S1) and the second signal (S2), and furthermore, by repeating measurements with different temperatures of the heater (30), the type and concentration of the gas can be calculated. Accordingly, according to the gas gauges (100, 100a, 100b), by correcting the gas concentration data according to the type of gas, the reliability of the gas concentration measurement can be increased.

[0055] The present invention has been described with reference to the embodiments illustrated in the drawings, but this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom. Accordingly, the true technical scope of protection of the present invention should be determined by the technical spirit of the appended claims.

Claims

1. A substrate having a through hole formed therein; A diaphragm formed on the substrate, comprising a first portion extending from one side of the substrate onto the through hole and a second portion extending from the other side of the substrate onto the through hole, wherein a first opening is formed between the first portion and the second portion that crosses the through hole; A heater disposed on one side of the first part facing the first opening and capable of transferring heat to the surroundings; A temperature control unit for controlling the temperature of the heater by adjusting the heating current supplied to the heater; A first sensor formed on the other side of the first part and for measuring the amount of conductive heat transferred from the heater through the first part by a conduction method; A second sensor formed in the second part above for measuring the amount of convective heat transferred from the heater across the first opening through the air inside the through hole in a convective manner; and A gas calculation unit comprising a first signal for conductive heat quantity measured by the first sensor and a second signal for convective heat quantity measured by the second sensor, wherein the first signal and the second signal obtained by changing the heating current supplied to the heater by the temperature control unit are used to obtain information regarding the type and concentration of gas in the air within the through hole. Hybrid type gas gauge.

2. In Paragraph 1, The above gas calculation unit calculates the concentration of air in the through hole using the ratio of the first signal to the second signal, Hybrid type gas gauge.

3. In Paragraph 1, The gas calculation unit obtains information regarding the type and concentration of the gas in the air using the first signals and the second signals, respectively, obtained when the first heating power and the second heating power are supplied to the heater by the temperature control unit. Hybrid type gas gauge.

4. In Paragraph 3, The gas calculation unit obtains information regarding the type and concentration of the gas in the air using a first ratio of the first signal to the second signal obtained when a first heating power is supplied to the heater by the temperature control unit, and a second ratio of the first signal to the second signal obtained when a second heating power is supplied to the heater by the temperature control unit. Hybrid type gas gauge.

5. In Paragraph 4, The above gas calculation unit is a hybrid type gas gauge that obtains information about the type and concentration of the gas in the air using the difference between the above first ratio and the above second ratio.

6. In Paragraph 4, The above gas calculation unit determines whether O2 gas and H2 gas are included in the air in addition to N2 gas by using the difference between the first ratio and the second ratio, based on the case where the air is N2 gas. Hybrid type gas gauge.

7. In Paragraph 1, It further includes a transparent conductive oxide film formed on the first portion on which the heater is disposed, and The above gas calculation unit further receives resistance information of the transparent conductive oxide film according to the heating power applied to the heater, Hybrid type gas gauge.

8. In Paragraph 1, The diaphragm includes second openings formed on both sides of the first sensor and third openings formed on both sides of the second sensor, and The second openings are formed to extend in a direction perpendicular to the first opening, and The third openings are formed to extend in a direction perpendicular to the first opening, Hybrid type gas gauge.

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